Aerosol heater with improved control means



Nov. 4, 1969 MARCOUX 3,476,293

' AEROSOL HEATER WITH IMPROVED CONTROL MEANS Filed Aug. 29, 1967' 2Sheets-Sheet 1 l8 5 W- 1 /6 Q 20 I L W Y J- L2 385 INSULATION S W-lINVENTOR,

Leo .Marcoux,

Aujy.

United States Patent U.S. Cl. 222-146 14 Claims ABSTRACT OF THEDISCLOSURE A heater-dispenser device for heating fluid materials passingtherethrough is disclosed. The heater consists of a spirally woundflattened tubular sheath containing an internal resistance heaterelectrically insulated therefrom. A solid-state element having atemperature-resistivity curve which reflects low resistance values atrelatively low temperatures and relatively small changes in resistancewith increasing temperature until an anomaly point is reached at whichpoint the resistance rapidly increases with slight increases intemperature. The element generates heat causing an increase inresistance until a thermal equilibrium is attained thereby limitingcurrent flow. A lamp is employed as an indicator to show when the systemhas generated sufficient heat and is ready for dispensing. Oneembodiment shows a heater-dispenser which is reciprocably mounted. Asecond embodiment shows a stationary heater-dispenser unit withreciprocably mounted actuating means.

Background of invention This invention relates to an improvedheater-dispenser device for use with pressurized containers. Moreparticularly it relates to an improved device which can heat a fluidmedium issuing from a pressurized package.

Pressurized containers have become widely used for packaging anddispensing fluids and fluid-like materials. It is desirable to elevatethe temperature of many such materials, such as, by way of example,windshield deicing fluids for automobiles, shaving lather, certainpaints and varnishes, hot fudge and similar food items, and so on.

Various prior art devices have been designed for this purpose. Generallythey have been of two basic types as exemplified by the United Statespatent to Lannert, 2,873,- 351, issued Feb. 10, 1959. This patentdiscloses a heat exchanger which is attachable to the outlet of anaerosol container. Fluid medium is directed through the heat exchangeras it is released from the container and is thereby heated. The heatexchanger is heated by an electric heater in one embodiment and by hotWater in another embodiment. The subject matter of the instant inventionrelates to improvements on the first-mentioned embodiment.

Aerosol containers employ a gas, such as Freon, under pressure to forcethe contents thereof out of the container when the discharge valve isopen. Since the containers are fabricated from relatively thin gaugematerials, it is important to keep the gas pressure at a safe level.Safe maxi- 'mum temperatures, e.g., 120 F., have been determined forsuch containers since elevating the temperature of the gas in a constantvolume increases the pressure thereof. Heaters used with aerosolcontainers, to be safe must not cause the temperature of the containerto approach these levels.

Electric heaters in prior art devices have had certain inherentlimitations, to name a few, they have necessitated relatively complex,expensive constructions in order to provide adequate safety and to keepthe heating device in the environs of a desired temperature by turningon and Patented Nov. 4, 1969 off the heating element current by use ofmovable contacts. They have drawn relatively large amounts of power,line voltage variations have caused variations in heater temperature,and extra parts have been required to calibrate the heaters and regulatethe temperature thereof. In copending application No. 504,944, filedOct. 24, 1965, now Patent No. 3,338,476, issued Aug. 29, 1967 animproved heater-dispenser is disclosed and claimed comprising asolid-state heater element having a large PTC characteristic which isused not only as a controlling element but also as the primary heatingelement.

Using the PAC element for the dual function of heat ing and controllinghas solved many of the prior art limitations; however, for certainapplications a less expensive structure is required.

One of the drawbacks which has prevented prior art devices from becomingcommercially successful for many applications is that the cost of thedevice has been too high in relation to the cost to the consumer of thepressurized container making it less attractive to the consumer. Withthis as a design parameter along with the other prior art limitationsreferred to above applicant has invented apparatus which meets all ofthe criteria mentioned above, resulting in lower cost for the PTCelement and a more efiicient heat transfer from the heater to the =fluidin the pressurized container while still maintaining the advantages ofthe system contained in my copending application.

It is therefore an object of this invention to overcome thedisadvantages mentioned supra and to provide a simple, inexpensive,reliable, sturdy heating device which is easv to fabricate and usefulwith aerosol containers.

It is another object of this invention to provide a heating deviceuseful with aerosol containers which results in minimal heat transfer tothe container.

Yet another object is to provide an aerosol dispenserheater which has aself-regulated temperature and has inherent compensation for linevoltage variations.

Another object is to provide a heater-dispenser which has a short warmup time and which is removably attachable to the outlet of thepressurized container to heat the contents as they issue therefrom.

The invention accordingly comprises the elements and combination ofelements, features of constructions and arrangements of parts which willbe exemplified in the structures hereinafter described, and the scope ofthe application of which will be indicated in the appended claims.

In the accompanying drawings in which two of the various possibleembodiments of the invention are illustrated:

FIGURE 1 is a circuit diagram of the circuit employed in the embodimentsshown in FIGURES 2 and 3;

FIGURE 2 is a cross-sectional view of the device constructed inaccordance with the invention with an elevational view of a pressurizedcontainer shown broken away;

FIGURE 3 is a cross-sectional view of a second embodiment of the instantinvention with an elevational view of a container shown partly incross-section and broken away.

Similar reference characters indicate corresponding parts throughout theseveral views of the drawings.

Dimensions of certain of the parts as shown in the drawings have beenmodified and/or exaggerated for the purpose of clarity of illustration.

A device 10, constructed in accordance with the invention, isillustrated in FIGURE 2. A pressurized container 2, which holds materialto be heated upon dispensing, such as shaving lather, mounts on itsoutlet stem 6 a heaterdispenser assembly 34. Assembly 34 comprisescup-shaped housing 36 provided with a central recession 38 which acts asa seat for the distal end portion of stem 6. An aperture 42 in therecession 38 is aligned to communicate with the bore of stem 6. Locatedin housing 36 is a heater formed of a thin tubular jacket 46 whichclosely encapsulates wire heating element 26. Jacket 46 is formed in aspiral providing a continuous spirally shaped passage 44 through whichthe foam material is adapted to pass. Jacket 46 may be constructed ofany good thermally conductive material, such as aluminum. A conventionalelectrical insulation is provided in jacket 46 to prevent shortcircuiting. This may be effected, for example, by anodizing the aluminumin a conventional manner or by coating the internal surface with a thinlayer of a conventional polymer. Cover plate 48 is fitted on top ofhousing 36 and attached thereto in any convenient manner as by crimping.For reasons which will be explained below, in order to limit heattransfer from heater 26, cover 48 may be constructed of or coated with athermal insulating material. Electrical insulation separate cover 48from element 24, further described below. Housing 36 and cover 48 areformed with egress portion 50.

Mounted on cover member 48 is a control element 24 composed ofsolid-state material which has as a chracteristic a large positivetemperature coeflicient of resistance (PTC). Polymers which can becrosslinked with carbon or other elements, such as carbon black filled,cross-linked polyethylene, e.g., No. 4510 obtained from CabotCorporation, 125 High St., Boston, Mass, are examples of one type ofmaterial. Another class of material is certain doped ceramics, such as,barium titanate doped with lanthanum, Ba La TiO Reference may be had toUS. Patent No. 3,338,476 for more detailed information on thepreparation of this material.

PTC element 24 is provided with conductive terminal layers 25 onopposite sides thereof. Layers 25 may, for example, be composed of asilver alloy coated by e lectroless soldering techniques known in theart.

Electrical insulation 64 which may be a conventional potting compound isconveniently employed as a support for several components of the device;viz, momentary contact switch SW-l, lamp 18 and plug member 60.

Line current is conducted by a conventional two wire cord L L L isconnected to conductor 28, thence to one end of a standard resistanceheater wire 26, the other end of heater wire 26 is connected byconductor 22 to one terminal layer 25 of the PTC control element 24.This layer 25 is also connected to one side of lamp 18 by conductor 20.The other layer 25 of PTC element 24 is connected to the other side oflamp 18 by conductor 16 and to one side of switch SW-l by conductor 14.Lastly, the other side of switch SW-l is connected to L by conductor 12.

Switch SW-l is provided with a push button 62 which is biased upwardlyby a spring (not shown). A stiffer spring 40 is mounted on stem 6 whichbiases assembly 34 upwardly as shown in FIGURE 2. The spring in switchSW-l is such that it can be depressed by application of a force onbutton 62 to actuate the switch without causing spring 40 to bedepressed. However, upon a greater force on button 62, the switch springwill act as a transfer member and spring 40 will be depressed to actuatethe valve of the pressurized contained.

Cover member 34 encloses the heater-dispenser unit 10 and is providedwith apertures 52, 54 and 56 to allow access for plug 60, push button 62and egress 50 respectively. Aperture 56 is made large enough' to permitlamp 18 to be seen by the operator of the device.

The operation of the device will now be explained. An initial force inthe direction of arrow 63 is exerted on button 62 of switch SW1depressing it from the phantom line position shown in FIGURE 2 closingthe momentary contacts bridging conductors 12 and 14 as best seen inFIGURE 1. It should be noted that this initial force is of a magnitudeless than that required to depress spring 40 as explained above. Currentflow thro g PT m rial 24 which in the cold state has a relatively lowresistance and thence through the main heater 26 and back to L Lamp 18is preferably of the voltage sensitive avalanche type such as a neonlamp, so that initially it will not conduct at the low voltage generatedacross the cold PTC element. The PTC material used for effectiveoperation of the device to permit close temperature control must have asacharacteristic a large positive temperature coeflicient of resistance,that is, material in which the percent change in resistance per degreechange in temperature in the so-called break or anomaly point is verylarge. Current flowing through element 24 generates heat in the elementraising its temperature until the anomaly point is reached beyond whichpoint the resistance of element 24 rises very rapidly. The resultantvoltage increase across the PTC element 24 causes the lamp to fire andalso deenergizes the main heater 26.

When light 18 conducts the user then applies sufficient force to button62 to depress spring 40 moving the assembly 34 from the phantom lineposition shown in FIGURE 2 to the full line position and therebyreleases the pressurized material from container 2. The material in thecontainer typically upon release from container2 turns into a foamysubstance containing many air bubbles and consequently is a very poorheat conductor. To optimize heat transfer from jacket 46 to the foam,the jacket is formed so that a maximum amount of surface area is exposedto the foam and the distance between the jacket wallsv defining passage44 is kept relatively small so that as much of the foam as ispractically possible will come in direct contact with the heatexchanger.

As an example, in one device constructed in accordance with the above,the line voltage is divided so that initially there is about 20 voltsacross the PTC element and about volts across the heater 26. A resultingcurrent of 1 ampere causes 20 watts of heat generated in element 24 andabout 100 watts in heater 26. The heater, due to its substantial heatmass, quickly heats up and stores the heat. The PTC element heats up dueto its own heat generation and acts as a thermal analog of heater 26.The PTC element 24 employed has an anomaly at approximately C. which isreached in about ten seconds. The PTC element 24 then takes virtuallythe total applied voltage, the heater voltage dropping to close to zero.Neon glow lamp 18 then turns on indicating that the system is ready todeliver hot aerosol fluid.

The system is especially useful for one shot type application sinceessentially all the heat generated by the heater is stored in thethermal mass of the heater with very little heat loss. The heater isthermally separated from surrounding parts consequently will lose mostof its heat to the aerosol fluid when it is passed therethroughresulting in a very efficient device. As mentioned above, the PTCelement 24 is designed so that it acts as a thermal analog of the heatertherefore due to its own heat generating capacity it could be remotelylocated from the heater 26. Preferably the PTC element is kept to asmall size and is used primarily as a control device and does notcontribute any substantial heat to the system.

This system also provides compensation for line voltage variation. Lowvoltage will cause reduced current flow which will in turn result inlower power in both element 24 and heater 26. This will cause the PTCelement 24 to heat up more slowly and consequently power will besupplied to heater 26 for a longer time so that the total heat generatedwill be approximately the same. High voltage will cause just theopposite reaction in element 24 so. that power will be supplied toheater 26 for a shorter time and again approximately the same total heatwill be generated.

It will be seen from the above that this device olfers many advantagesover various prior art devices. There is no standby power drain sincethe device is activated for only the short period required for warm up.The warm up is extremely fast. The neon glow lamp provides convenientindication in comparison with copending application, now Patent No.3,338,476, a lower cost PTC element design and an even more eflicientheat transfer are provided.

It will be obvious to those skilled in the art that rather than usinghouse current a rechargeable battery could be employed as the powersource. The device could be connected to a charger when not in use.

If it is preferred to have the neon lamp glow until the Warm up periodis completed and then turn off, lamp 18 can be connected across heater26 instead of PTC element 24.

Turning now to a second embodiment reference may be had to FIGURE 3.Device 100 is shown comprising essentially the same heating element(wire 26 and jacket 46) defining the same passage 44. Therefore, thedescription for this portion of the device and for the electricalcircuit which is the same as that for FIGURE 2 and shown in FIGURE 1will not be repeated. In this embodiment separate actuating means areprovided for the heater circuit and for the actuator of the aerosolcontainer valve. Further, the heater-dispenser assembly is stationaryrelative to support 134 resulting in a more durable device.

Electrical insulation or support 134 in this embodiment is molded of aconventional polymeric material and is provided with a chamber in whichthe heater jacket 46 is located. Plate 150 encloses passage 44 and isconstructed out of heat and electrical insulation to provide thermalseparation between the PTC element 24 and heater 26 providing moreaccurate control capability for the element 24. Support 134 is formedwith a hub portion 145 which mounts a reciprocably movable slide 144with an axial channel 146 therein. A bore 136 is provided in hub 145 inwhich motion transfer member 138 slides. A recessed annular area 140 islocated in transfer member 138 to seat one end of spring 142. The otherend of spring 142 is seated adjacent hub 145 causing transfer member 138to be upwardly biased as seen in FIGURE 3. Button 166 is mounted in bore167 of cap 158 and is adapted to contact transfer member 138. Stopmember 168 is located on button 166 to limit the upward travel thereof.

Aperture 139 in hub 145 communicates with passage 44. Aperture 141located in wall 148 of support 134 communicates with passages 44 andegress 141 in wall 148.

Button 160, slidably mounted in bore 164 of cap 158, is adapted tocontact switch SW-l. A spring in switch SW-l (not shown) biases button160 upwardly, the movement of which is limited by stops 162.

Support 134 has lip members 132 and 152 which releasably snap on to theouter rim and nozzle 9 of container 3.

Cap 158 interfits with wall 130 of support 134 to enclose the device.Cap 158 has a transparent portion 172 to permit visual recognition ofthe energization of lamp 18.

In this embodiment the user initiates the warm up by depressing button160 in the direction of arrow 161 from the phantom line position inFIGURE 3 to the full line position. This activates switch SW-1 and theheating action occurs as in the FIGURE 2 embodiment. When lamp 18 glows,the user then depresses button 166 in the direction of arrow 167 fromthe phantom line position to the solid line position which causes slide144 to move downwardly dislodging the ball valve 8 from its seatpermitting the fluid to discharge through channel 146, aperture 139 andinto passage 44 wherein it is heated by contact with heat packet 46 andthen is ejected through aperture 141 and out of egress 143.

Thus it will be seen that all the objects of the invention arefulfilled.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

It is to be understood that the invention is not limited in itsapplication to the details of construction and arrangement of partsillustrated in the accompanying drawings, since the invention is capableof other embodiments and of being practiced or carried out in variousways. Also, it is to be understood that the phraseology or terminologyemployed herein is for the purpose of description and not of limitation.

As many changes could be made in the above constructions withoutdeparting from the scope of the invention, it it intended that allmatter contained in the above description or shown in the accompanyingdrawings, shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. A heater-dispenser device usable with aerosol containers comprising:

(a) means defining a passage and having an ingress and an egress,

(b) a solid-state control element having a steep-sloped PTCtemperature-resistivity curve,

(c) a load connected in series with said control element and in heattransfer relation to said passage defining means, and

(d) means to energize said control' element and load.

2. A device according to claim 1 further including:

(e) an indicating device connected in parallel across said controlelement.

3. A heater-dispenser device in accordance with claim 1 in which theload is a spirally configured, flattened tubular sheath having aninternal resistance wire heater therein.

4. A heater-dispenser device according to claim 2 in which the indicatordevice includes an avalanche-type lamp.

5. -A heater-dispenser device according to claim 1 which is located in adetachable housing which is adapted to fit on top of an aerosol typecontainer.

6. A heater-dispenser device according to claim 5 which is reciprocablymounted in the housing.

"7. A heater-dispenser device according to claim 5 which is fixedlymounted on the housing and a reciprocable slide is mounted to actuatethe valve of the aerosol container.

8. A device according to claim 1 in which the control element iscomposed of Ba La TiO 9. A device according to claim 1 in which thecontrol element is composed of a carbon black filled polymer.

10. A device according to claim 5 including a first and second spring,the second spring less stifi? than the first spring, the first springbiasing the device away from the aerosol container, and the secondspring biasing energizing means in an open direction.

11. Heater-dispenser apparatus comprising:

(a) a support member having an axially bored hub,

a bottom wall and depending side walls with an egress therein; the hubbottom and side walls forming an annular chamber,

(b) heating means located in the chamberand defining a spiral pasasge,

(c) a cover plate enclosing the passage and forming a thermal barrier;

(d) a motion transfer member slidably mounted in the bore of the supportmember, and adapted upon predetermined movement thereof to actuate avalve of an associated container,

(e) means biasing the transfer member away from the x-the valve, (f). asteep-sloped PTC element mounted on the support and designed to be athermal analog of the heating means,

(g) means connecting the heating means and the PTC element in seriesrelation to a power source, whereby when the heating means has generatedand stored a predetermined amount of heat the resistance of the PTCelement will rapidly increase to limit the current to the heating means.

12. Apparatus according to claim 11 in which indicator 7 means isprovided to indicate when the apparatus is in a heated condition.

13. Apparatus according to claim 12 in which the indicating meansincludes a neon lamp connected across the PTC element.

14. Apparatus according to claim 11, further comprismg:

(h) a cover which interfits with the support member,

(i) a first and second push button slidably mounted in the cover, thefirst button adapted to contact the 10 transfer member; the secondbutton adapted to actuate the electrical circuit.

References Cited UNITED STATES PATENTS STANLEY H. TOLLBERG, PrimaryExaminer

